Running Podman on Mac Terminal

How to run Podman commands directly from macOS terminal

I've found some articles explaining how to run Podman on top macOS [1], but the adopted approach was using podman-machine, which is a wrapper for an instance VM running on top of Virtulbox.

Since my goal was being able to run Podman commands directly from Mac terminal, I started looking for approaches alike the one I currently have for Docker (remote socket).

Podman is a tool for running Linux containers, same as we have for Docker. However, Podman out-of-the-box can only manage containers running on Linux instances, since it relies on an OCI compliant Container Runtime (runc, crun, runv, etc) to interface with the OS and create the running containers.

In a nutshell, we can do this from a macOS as long as you have access to a Linux box either running inside of a VM on the host or available via the network.

For running Linux on top of Mac, I've decided to use Multipass, rather than Virtualbox. Multipass provides a CLI to launch and manage instances of Linux. The downloading of a minty-fresh image takes a matter of seconds, and within minutes a VM can be up and running. Multipass relies on HyperKit which is an open-source hypervisor for macOS hypervisor.

At glance, the steps were:

1. Install Multipass and Podman on Mac;
2. Launch an Ubuntu 20.10 instance with cloud-init metadata same we do for AWS, Azure, GCP, etc;
3. Cloud-init will perform the minor customizations we need on the Linux instance (required packages and SSH settings);
4. Setup a Podman remote connection on Mac;
5. Enjoy the view.

Getting the Hands Dirty

• Install Multipass and Podman to your MacOSX:

$ brew install multipass podman

• List Multipass available images:

$ multipass find                                                                                           
Image                       Aliases           Version          Description
...
20.10                       groovy            20210130         Ubuntu 20.10

• Update the cloud-config.yaml file with your SSH public key.

...
users:
  - name: ubuntu
    ssh-authorized-keys:
      - ssh-rsa AAAAB3Nz... [email protected]
...

• Rollout a new Ubuntu 20.10 instance using Cloud-Init definitions:

$ multipass launch -c 2 -m 2G -d 10G -n my-podman 20.10 --cloud-init ubuntu-20.10/cloud-config.yaml
Launched: my-podman

$ multipass list                                                                                      
Name                    State             IPv4             Image
...
my-podman               Running           192.168.64.2     Ubuntu 20.10

The above command will create a Ubuntu instance named my-podman with 2 vCPUs, 2GB RAM and 10GB Storage. Take note of the instance IPv4 (e.g. 192.168.64.2).

• Once the instance is created, jump into it and run the podman info for confirming the daemon status:

$ multipass shell my-podman
Welcome to Ubuntu 20.10 (GNU/Linux 5.8.0-41-generic x86_64)
...
ubuntu@podman-1:~$ podman info 
host:
  arch: amd64
  buildahVersion: 1.18.0
  cgroupManager: cgroupfs
...
  cpus: 2
  distribution:
    distribution: ubuntu
    version: "20.10"
...
  kernel: 5.8.0-41-generic
...
runRoot: /run/user/1000/containers
...
version:
  APIVersion: 2.1.0
  Built: 0
  BuiltTime: Thu Jan  1 01:00:00 1970
  GitCommit: ""
  GoVersion: go1.14.7
  OsArch: linux/amd64
  Version: 2.2.1

• Return to Mac terminal and after adding your SSH private key to the system keyring, create a new Podman connection informing the Podman’s instance IPv4:

$ ssh-add $HOME/.ssh/id_rsa

$ podman system connection add multipass \
ssh://[email protected]/run/user/1000/podman/podman.sock

• List the Podman connections list:

$ podman system connection list                                                                       
Name        Identity  URI
multipass*            ssh://[email protected]:22/run/user/1000/podman/podman.sock

• Run *podman info* once again, but now from Mac terminal:

$ podman info 
host:
  arch: amd64
  buildahVersion: 1.18.0
  cgroupManager: cgroupfs
...
  cpus: 2
  distribution:
    distribution: ubuntu
    version: "20.10"
...
  kernel: 5.8.0-41-generic
...
runRoot: /run/user/1000/containers
...
version:
  APIVersion: 2.1.0
  Built: 0
  BuiltTime: Thu Jan  1 01:00:00 1970
  GitCommit: ""
  GoVersion: go1.14.7
  OsArch: linux/amd64
  Version: 2.2.1

• Now, start a new container and enjoy:

$ podman run -it busybox sh
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